1. Field of the Invention
The present invention relates to a method for displaying received signal strength bars in a wireless terminal device, and more particularly to a method for displaying received signal strength bars in a wireless terminal device taking into consideration the received field strength of the terminal device and interference signals around the terminal device.
2. Description of the Related Art
Generally, a wireless terminal device displays received signal strength bars at a predetermined position on a display unit in order to provide a user with information of its communication quality (e.g., a phone conversation quality) and data transfer speed in real time. That is, the wireless terminal device expresses whether the communication quality or data transfer speed is good or bad by varying the number of bars. In general, a larger number of bars indicates a higher communication quality or data transfer speed, and a smaller number of bars indicate a lower communication quality or data transfer speed.
FIG. 1 is a block diagram schematically showing the configuration of a general wireless terminal device. Referring to FIG. 1, the wireless terminal device includes a database (DB) 10, a receiving unit 20, a controller 30, and a display unit 40. Descriptions of a transmitter, a key input unit, a microphone, and a speaker, which are included in a usual wireless terminal device, are omitted to avoid obscuring this description with unnecessary detail.
The database 10 stores and manages information required for performing a normal operation of the wireless terminal device. The receiving unit 20 receives data from an external network access device (e.g., a base station) and transmits the received data to the controller 30. The controller 30 controls the overall operation of the wireless terminal device. The display unit 40 displays the operation status of the terminal device and externally-inputted information under the control of the controller 30.
FIG. 2 is a flowchart illustrating a method for displaying received signal strength bars of the wireless terminal device according to one example of the prior art. Referring to FIGS. 1 and 2, the prior art method for displaying received signal strength bars is described as follows.
The receiving unit 20 receives predetermined data transmitted from the external network access device such as a base station and transmits the received data to the controller 30. The controller 30 analyzes the data received from the receiving unit 20 to obtain an RSSI (Received Signal Strength Indicator) value in step S10, and, based on the collected RSSI value, determines the number of received signal strength bars to be displayed on the display unit 40 in step S20. To this end, the controller 30 refers to a predetermined reference table stored in the database 10. The predetermined reference table includes information on the number of received signal strength bars previously set in correlation with each of the ranges of the RSSI value.
When the number of signal strength bars for representing the current communication quality or data transfer speed is determined in the step S20, the controller 30 enables the display unit 40 to display the signal strength bars in step S30.
In such a manner, the mobile terminal device of the prior art only refers to the RSSI value in order to display the signal strength bars on its screen. In other words, the conventional method for displaying the signal strength bars does not consider any peripheral conditions such as interference. Therefore, in the prior art, a large number of signal strength bars are displayed if received field strength is high, irrespective of a high intensity of peripheral interferences, whereas a small number of signal strength bars are displayed if received field strength is low, irrespective of a low peripheral interference.
Even when the received field intensity is high, actual communication quality or data transfer speed may be poor provided that the intensity of peripheral interferences is high, but the prior art method will be subject to the error of displaying a large number of signal strength bars in such a case, indicating that the communication quality or data transfer speed is good, and vice versa.
In addition, the prior art method obtains an average RSSI value based on five RSSI values read, and updates the signal strength bars at intervals of 250 ms using the obtained average value, which leads to instability in the displaying of the signal strength bars.